Respuesta :

P=2(L+W)
60=P=2(L+W)
60=2(L+W)
divide by 2
30=L+W

given
W=-2+7L
subsitute
30=L+W
30=L-2+7L
30=8L-2
add 2
32=8L
divide by 8
4=L


sub back
W=-2+7L
W=-2+7(4)
W=-2+28
W=26

width is 26cm
length is 4cm